1. Field of the Invention
The present invention relates to aquariums and more specifically, to a high-power plastic aquarium heater for aquarium, which utilizes a heat source made by winding a nickel-chrome strip on a mica tube.
2. Description of the Related Art
To keep the water in a big-scale aquarium warm, a high-power heater shall be used. A conventional high-power heater for this purpose normally uses a heating coil formed of a nickel-chrome wire for generating heat upon connection of electricity. This heating coil is wound on a thermal insulative holder made of ceramics or mica, and then mounted in a tubular casing. Similar designs are seen in U.S. Pat. No. 7,293,914, entitled “Temperature detecting heater with indicating structure for aquarium”, and U.S. Pat. No. 6,097,007, entitled “Aquarium water temperature controller”, both issued to the present inventor. The tubular casing can be a metal tube, ceramic tube, glass tube or plastic tube. A metal tube does not break and provides excellent heat spreading effect. However, a metal tube tends to cause electric leakage and to get rusted. A ceramic tube or glass tube avoids electric leakage and rust problems, however it may break easily.
A plastic casing is ideal for holding a heating coil in an aquarium. However, it is difficult to position a thermal insulative holder with a heating coil in the longitudinal center axis of a plastic casing accurately. If a thermal insulative holder is not accurately positioned in the longitudinal center axis of a plastic casing, heat energy cannot evenly distributed in all directions through the plastic casing. Further, because the heating coil generate heat in different directions, the performance of the heater is low.